MILWAUKEE (CBS 58) -- You know those annoying mailers and phone calls you get about your expiring car warranty? You're not alone.

The Better Business Bureau has received more than 500 complaints in the last year about companies offering vehicle service contracts. They say they have you covered, but it's often not what it looks like.

"They make it sound urgent. Your vehicle warranty's about to expire or it has expired and you need to sign up or get another one or renew it," said Lisa Schiller with the Better Business Bureau of Wisconsin.

It can be confusing to get a letter in the mail because you think it comes from your car's manufacturer or dealership. But these are private companies trying to get you to sign up for their coverage that can cost more than $100 a month.

The contracts can be difficult to get out of and then, say you do have a problem, there's a good chance you'll still have to pay entirely out of pocket!

"You're paying into this contract thinking that when something goes wrong with your car and your car breaks down, you take it to the local repair shop to get it fixed and then you're told that the item is not covered," Schiller says.

That's why the BBB says it's so important to read what you actually get when you sign the contract.

The three companies that had the most complaints against them were Car Shield, Motor Vehicle Services, and Safeguard Auto Direct